Xuan K.T.,Science and Technology Institute
Proceedings of the 2015 7th IEEE International Conference on Cybernetics and Intelligent Systems, CIS 2015 and Robotics, Automation and Mechatronics, RAM 2015 | Year: 2015
This paper addresses the development of a high precision low-cost Inertia Measurement Unit (IMU) where MEMS-based accelerators, gyroscopes, magnetic sensors and an extended Kalman filter are used in a real-time signal processing system. Integral operation of inertial sensor signals leads to velocity and position estimation drift that increases with time. The drift has been eliminated by our algorithm of Kalman Filtering technique with geomagnetic information. The algorithm are tested in Matlab environment and implemented on a PIC microcontroller to estimate the attitude of an object in space. MATLAB/Simulink Embedded tools and compiler C30/MPLAB are used to design, compile and download directly into the target. The processing rate of 100Hz with real-time floating point calculation can be achieved for the extended Kalman algorithm using a Microchip 16 bit dsPIC33f256. © 2015 IEEE. Source
Duailibi M.T.,Federal University of Sao Paulo |
Duailibi M.T.,National Institute of Science and Technology |
Kulikowski L.D.,Federal University of Sao Paulo |
Kulikowski L.D.,University of Sao Paulo |
And 8 more authors.
Journal of Molecular Histology | Year: 2012
Human adult stem cells (hASCs) offer a potentially renewable source of cell types that are easily isolated and rapidly expanded for use in regenerative medicine and cell therapies without the complicating ethical problems that are associated with embryonic stem cells. However, the eventual therapeutic use of hASCs requires that these cells and their derivatives maintain their genomic stability. There is currently a lack of systematic studies that are aimed at characterising aberrant chromosomal changes in cultured ASCs over time. However, the presence of mosaicism and accumulation of karyotypic abnormalities within cultured cell subpopulations have been reported. To investigate cytogenetic integrity of cultured human dental stem cell (hDSC) lines, we analysed four expanded hDSC cultures using classical G banding and fluorescent in situ hybridisation (FISH) with X chromosome specific probe. Our preliminary results revealed that about 70% of the cells exhibited karyotypic abnormalities including polyploidy, aneuploidy and ring chromosomes. The heterogeneous spectrum of abnormalities indicates a high frequency of chromosomal mutations that continuously arise upon extended culture. These findings emphasise the need for the careful analysis of the cytogenetic stability of cultured hDSCs before they can be used in clinical therapies. © Springer Science+Business Media B.V. 2011. Source
Currently pursued at laboratory scale only, the results of this work have been published in the Construction and Building Materials journal. They also form part of Brazilian student João Cláudio Bassan de Moraes's master's dissertation, directed by lecturer Mauro Tashima, who completed his PhD at the UPV and is currently lecturing at Unesp. Talking to us about the project, Jordi Payá, researcher at the Concrete Science and Technology Institute (ICITECH) at the UPV, explains: "The harvester strips the cane, discarding the tops and leaves as waste. This is the raw material we work with, sugar cane straw". In total around 650 million tonnes of sugar cane are harvested in Brazil every year. Of this, between 15 and 20% corresponds to sugar straw, which is left on the field and either burned or left to decay naturally. So far, the international research team has been able to obtain concrete using 30% less Portland cement, substituting it with the ashes obtained from burning the sugar cane straw. "The cement itself is the most expensive and most polluting ingredient of concrete, which makes the benefits [of this new method] as much economic as environmental. We are also making use of a by-product that is currently unexploited, with all the benefits that this entails." To burn the waste, UPV and Unesp researchers have designed a bespoke combustion burner, into which the raw material must be fed following a strict procedure. "Through this process we obtain ashes that are very reactive to the cement, a quality that is very important to the mechanical performance of the resulting concrete, to its resistance to compression, for instance" (Payá). Work has focused primarily on the microstructural analysis of the concrete. "In the lab we analyse the chemical compounds of the ashes and of the compounds produced during the reaction with the cement, in order to assess their performance in the final product", explains Payá. Future work would include studying indicators related to the durability of mass and reinforced concrete. The ICITECH research team also studies the use of other agricultural waste as a cement substitute, including the bamboo leaf. More information: J.C.B. Moraes et al. Assessment of sugar cane straw ash (SCSA) as pozzolanic material in blended Portland cement: Microstructural characterization of pastes and mechanical strength of mortars, Construction and Building Materials (2015). DOI: 10.1016/j.conbuildmat.2015.07.108
Light pollution prevents a third of humanity from seeing the night sky. LED lighting is about to make the problem worse. Back in 1994, the Northridge Earthquake caused major blackouts in the Los Angeles area. During the hours of darkness, something strange happened. People began to call 911 to report a strange ethereal light in the sky. What they were actually seeing was the Milky Way. Light pollution was so bad in the City of Angels that many people had never seen our galaxy. And that raises an interesting question. Just how bad has light pollution become in the years since then, and how is it set to change? Today we get an answer thanks to the work of Fabio Falchi at the Light Pollution Science and Technology Institute in Thiene, Italy, and a few pals, who have measured light pollution levels across the globe in unprecedented detail. These guys report that the luminous fog that began to fill the atmosphere during the Industrial Revolution has never been thicker, and that most people in Europe and America cannot see the night sky clearly. Their method makes use of a polar orbiting satellite called the Suomi National Polar-Orbiting Partnership satellite, a weather satellite operated by the National Oceanic and Atmospheric Administration. It orbits the globe from pole to pole once every 24 hours and so peers down on every part of the planet as it rotates beneath. In this way it can build up a composite image over time to allow for cloud cover and changes in artificial lighting on the surface. The new data was gathered over six months in 2014. Falchi and co then crunched this data to produce a new generation of maps of light pollution. The results make for impressive viewing. Falchi and co have created an atlas of light pollution for the entire planet that reveals how bad the problem has become. “We found that about 83% of the world’s population and more than 99% of the U.S. and European populations live under light-polluted skies,” they say. One measure of the severity of the problem is whether people can see the Milky Way. By this reckoning, the problem is severe. “Due to light pollution, the Milky Way is not visible to more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans,” say Falchi and co. Not everywhere is drowning in light, though. The team say the countries with the populations least affected by light pollution are Chad, Central African Republic, and Madagascar, with more than three-quarters of inhabitants living under pristine sky conditions. Others are not so lucky. The worst affected country is Singapore, where the entire population lives under skies so bright that their eyes cannot fully dark-adapt to night vision. Here the night never gets darker than early twilight. And the problem is set to get worse as many countries switch from high pressure sodium lighting to white light LEDs, which are much more energy-efficient. The problem with these LEDs is that they generate light across a much broader part of the spectrum visible to the human eye. Falchi and co say they are 2.5 times more light-polluting. Another problem is brewing because the sensors on the Suomi satellite are unable to pick up light in the blue part of the spectrum, and so will not register it in future measurements of light pollution. Nevertheless, there is hope. Various places have begun to enact light-pollution legislation to prevent further damage to the night sky—for example, Lombardia and most other Italian regions, Slovenia, two regions in Chile, and part of the Canary Islands. Such legislation is hugely important for astronomers but it has other consequences, too. Not least is the cultural importance of seeing the night sky and understanding Earth’s place within it. Falchi and co imagine two future scenarios. “Perhaps the current generation will be the final generation to experience such a light-polluted world, as light pollution is successfully controlled,” they say. “Alternatively, perhaps the world will continue to brighten, with nearly the entire population never experiencing a view of the stars, as in Isaac Asimov’s Nightfall novel and short story.” The prospect of people so scared by the pristine night sky that they call the police is a sad one that is already a reality. Let’s hope the former scenario comes to fruition. If nothing else it will significantly increase the beauty of the night sky for all. Ref: arxiv.org/abs/1609.01041: The New World Atlas of Artificial Night Sky Brightness
Sisbrick is a new class of earthquake-resistant building materials that seismically isolates partition walls from the main building structure, significantly reducing the tension between these two elements and, therefore, the damage incurred. Researchers from the Universitat Politècnica de València (Polytechnic Univ. of Valencia, UPV) have designed a new seismic isolator that improves the way buildings respond to earthquakes. The key to the Sisbrick, as the invention is known, lies in the way different materials have been combined to achieve two main effects: it is able to absorb horizontal seismic movements, while also supporting vertical loads (for instance, partition walls) that act on the integrity of the building frame. Designed specifically for use in partition walls, its brick form means it can be readily incorporated into traditional construction techniques, without the need for additional measures or equipment. Techniques and special bricks to improve the way buildings respond to earthquakes are already available on the market. However, what sets Sisbrick apart is its approach to partition walls. As researcher Luis Pallarés at the UPV’s Concrete Science and Technology Institute (ICITECH) explains, these structures greatly condition a building’s response to a seismic event. Merely making partition walls more resistant does not address the more widespread damage caused by earthquakes. The Sisbrick’s large capacity to absorb the horizontal movements caused by earthquakes seismically isolates the partition walls from the main building frame: “They effectively serve as an insulating barrier, avoiding the transfer of loads from these partition elements to the main structure. By doing so, their impact on overall structural integrity in the face of an earthquake is greatly reduced” (Pallarés). This also brings real seismic response into line with projected seismic response as calculated at the building design stage. Francisco Javier Pallerés, also of ICITECH, tell us that “today, seismic calculations only take into consideration the structure of the building frame and do not consider the partition walls, despite the clear and widely-reported influence they have on a building’s response to earthquakes”. By isolating the partition walls from the main frame, these calculations become more reliable. On top of the convenient brick form, only a relatively small amount of these bricks is needed to achieve this seismic isolation. Laboratory testing proves that, if the bricks are arranged in a specific way, just a small amount can afford significant gains in seismic wave absorption. Specifically, partition walls that incorporate Sisbricks can absorb horizontal movements in the order of three times greater than those that do not. This translates into considerably less tension in the partition walls, meaning correspondingly less tension is transferred to the building frame during earthquakes. The Sisbrick has been patented by the UPV. Testing is currently being carried out into the thermal and acoustic isolation afforded by this material, in order to comply with the specifications of the Building Code. The team at ICITECH is currently looking for collaborators for the implementation, manufacture and commercialization of this product.